In a light-emitting element (LED: Light Emitting Diode) of a surface emitting type, on the upper surface or the lower surface of which an electrode is provided, a part of emitted light is blocked by the electrode. The light-emitting element has a poor thermal conduction property and has a limit in an increase of current density.
The light-emitting element of the surface emitting type includes a Lambertian radiation pattern. The full width at half maximum of the Lambertian radiation pattern is as wide as, for example, 120 degrees. Therefore, it is difficult to narrow emitted light.
On the other hand, a semiconductor laser (a Diode Laser or a Laser Diode: LD) can emit laser light having sharp directivity from a very small light emitting region of a side surface. Therefore, for example, an optical fiber or the like having a small incident sectional area is used as a light guide member for guiding laser light and a wavelength conversion material (a phosphor, etc.) provided in a position away from a light-emitting element is excited by the laser light to emit light. Consequently, the semiconductor laser can be applied as an excitation light emission source that causes a region corresponding to the length and the width of the phosphor to emit light. The excitation light emission source can be used in a fog lamp for an automobile, a backlight light source of a display device, an optical sensor light source, a linear light source for an image reading device, a light source for general lighting, and the like.
In such uses, a light emitting device excellent in a reduction in size, a thermal conduction property, and a mounting property and rich in reliability is necessary.